Metallurgical heating-furnace.



E. C. WALKER & A. S. MOSES.

METALLURGICAL HEATING FURNACE.

APPLICATION FILED JAM-3.1916.

Patented Nov. 27, 1917.

2 SHEETS-SHEET I.

E. C. WALKER (Q A. S. MOSES.

METALLURGICAL HEATING FURNACE.

APPLICATION FILED JAN. 3. 1916.

Patented Nov. 27', 1917.

Y 2 SHEETS-SHEET 2- UNIT e r-nuns rn run r @FFJIGE.

EDWARD C. WALKER AND ASHELEIGH S. MOSES, OF ST. LOUIS, MISSOURI, A$SIGNORS TO GEORGE M. ILLGES, OF ST. LOUIS, MISSOURI.

METALLURGICAL HEATING-FURNACE.

Patented Nov. 25?, 1121?.

Original application filed June 11, 1913, Serial No. 773,119. Divided and this application filed. January 3, 1916. Serial 1\To.69,795.

To all whom it may concern:

Be it known that we, EDWARD C. WALKER and AsHnnniorr S. Mosns, citizens of the United States, and residing at St. Louis, in the State of Missouri, have invented a certain new and useful Improvement in Metallurgical Heating-Furnaces, of which the following is a specification.

This invention relates to coal burning metallurgical heating furnaces adapted to furnish heat by gases forming a reducing atmosphere.

A furnace of this type is disclosed in an application filed June 11, 1913, Serial No. 773,119, and of which the present applica tion is a division.

In the operation of such furnaces, particularly, when employed in the smelting of zinc, it is necessary to maintain a heating gas in the heating chamber of the furnace under pressure, and this heating gas must furnish a reducing atmosphere. It is of great importance that the quality and quantity, together with the temperature of the gas, be capable of accurate control in order that the temperature and composition of the heating gas in the heating chamber of the furnace be maintained-constant and at a predetermined value.

One of the objects of this invention, therefore, is to construct a furnace of the above type which will deliver heating gases to the heating chamber, which furnace is provided with means for automatically as well as manually regulating and controlling the quality, quantity and temperature of the heating gases delivered.

Another object is to construct a furnace of the above type which will be automatic in its operation, in which this automatic operation can be varied at will, and which will require a minimum of attendance.

Further objects will appear from the detail description taken in connection with the accompanying drawings, in which:

Figure 1 is a longitudinal vertical section through a furnace embodying this invention,

the section being taken on the line 1--1, Fig. 2;

Fig. 2 is a transverse section on the line 22, Fig. 1;

Fig. 3 is a section on the line 3-3, Fig. 2, parts being shown in elevation;

Fig. 4: is an end elevation of a part of the operatin mechanism looking in the direction of t e arrow 2, Fig. 1; and,

Fig. 5 is a plan of the part of the operation mechanism shown in Fig. 4.

Referring to the accompanying drawings, 10 designates the heating chamber of a furnace of the reverberatory type having ahearth 11 and an arch 12. This furnace may be of well known construction. The burner orheater structure comprises a body 13 of masonry arranged to form a vertical fuel chamber or shaft 14 having end walls 15 and 16. This end wall 15 terminates below the roof to form an outlet passage 17, and provides a bridge wall between the fuel chamber and the heating chamber of the reverberatory furnace. The bottom of the furnace is provided with wind boxes 18, which are preferably formed of a cast iron framework set into the back wall 15, and

"having twyers 19 opening into the fuel chamber. The inside faces of the wind boxes are preferably faced with fire brick 20 set into the metal. A casing 21, extending under and around the back wall 15, and having an end wall 22, is bolted to the wind boxes to form an ash pit. End brackets or standards 23 are provided with wheels 25 resting on tracks 26, whereby the heater structure may be moved toward and from the furnace chamber 10. A joint 27 is made between the heater structure and the furnace chamber structure, and this joint is filled with mud or mortar when the parts are in position. The fuel chamber or shaft 1 1 is shaped as shown in the drawings, so as to form a vertical shaft, contracted at the bottom, having a row of twyers on each side and open at the bottom to the ash it.

The fuel chamber 14; as a feed opening 30 in its roof, and this opening has a metal support or lining 31 provided with cross braces 32, and this lining is further provided with brackets 33 forming end bearings 34 for a feeding member 35. This feeding member is positioned underneath a hopper 36 supported by the lining. The hopper is inclosed by a casin 37 having an air pipe connection 38 provi ed with a regulating Valve 39. The feeding member has a shaft 40 having rigidly mounted thereon an arm 41 connected by a link 42 with an arm 43 on a rock shaft 44 supported in bearing brackets 45 on the heater structure. The arm is slotted, and the connection between this arm and the link 42 is made through a clamping bolt 46, whereby this clamping bolt may be adjusted in the slot to adjust the movement of the feeding member 35. This feeding means is of well known construction, and its operation is well understood. As the feeding member 35 is oscil lated laterally under the hopper, it operates to feed coal from the hopper, and the amount of feed is varied by varying the extent of Ehe lateral movements of the feeding mem- A ram 50 is sustained beneath the lower open end of the fuel shaft 14 by means of a supporting shaft 52 having bearing in arms 53 keyed to a shaft 54 journaled in suitable bearings and provided with a rigid arm 57 connected by a link 58 with an arm 59 on the rock shaft 44. There is also rigidly attached to the shaft 52, which extends outward through a vertical slot 60 formed in the wall 22 of the casing, an arm 61 connected by a link 62 with an arm 63 on the rock shaft 44, which is also provided with a slotted arm 64 adjustably connected with an operating rod 65 adapted for reciprocation from any suitable source of power. The links 58 and 62 have adjustable slot and bolt connections respectively with the arms 57 and 61, while the arm 63 is provided, at an intermediate point, with a hole 66 adapting the upper end of link 62 for an adjustment on said arm. The connections thus described are such that, upon operation of the rock shaft 44 through the medium of its operating rod 65, the feeding member 35, and also the ram 50, will be actuated, and by making certain adjustments of said connections, the ram can be caused to move vertically or horizontally, and these movements of the ram and also the oscillation of the feeding member can be independently varied, all in the manner and for the purposes fully set forth in the above noted application, to which reference may be had for a more detailed description of this part of the apparatus.

The wind boxes 18 open into the ash pit through openings 70.

The ash pit has a discharge opening 71 closed by a slide 72 having an operating handle 73 extending outside of the front wall 22. It will, therefore, be noted that the air from the wind boxes enters the ash pit at one end, while the ash pit discharge is located at the other end. The corners of the .ash pit walls are provided with fillets, as shown at 74, and the openings slant toward the front wall, as shown in Fig. 1. The purpose of this construction is to clear the ash pit of ashes. When the slide 72 is opened the air in the ash pit will force the ashes out through the discharge opening. In view ofthe fact that the air enters the ash pit at the end opposite where it is discharged, this air will act to sweep out the ashes from one end to the other. The fillets 74 operate to gradually change the direction of the air to promote the sweeping action.

The air connections to the Wind boxes 18 are made through pipes 75 connected with the main air supply pipe 76, which also delivers air to the pipe 38 through a pipe connection 77. The air in the pipe 76 is at a comparatively high pressure, usually several times as high as the pressure when finally delivered to the bed of fuel by the twyers and the ash pit. Thus, where the air delivered by the twyers and the ash pit through the bed of fuel is normally two ounces per square inch, then the pressure in the pipe 76 will inch. This is accomplished by making the pipes 75 of small diameter and sufficiently long so that they will act as resistances to reduce the pressure of the air as delivered into the wind boxes, and as delivered by the twyers and the ash pit through the bed of fuel. The pipe 75 may also be provided with regulating valves 8, whereby the resistance may be slightly varied to regulate the pressure of the air delivered into the furnace chamber, and with cut off valves 79, whereby the supply may be entirely cut off.

The fuel, such as coal, is fed into the fuel chamber or shaft from the top, and on top of the fire. A comparatively deep bed of coal is maintained in the fuel chamber so as to form a heating gas containing considerable hydrocarbons and free carbon monoxid in order to produce a reducing atmosphere in the heating chamber of the furnace. The ram 50 is moved vertically to stoke the fire and laterally to purge the fire. As the ram moves vertically it will break up and stir up the bed of fuel, and as it moves laterally it will shake out and discharge the ashes. The amount of stoking and purging can be varied by varying the vertical and lateral movements of the ram. The air is delivered to the bed of fuel by the twyers 19 and from the ash pit, since this ash pit is maintained be siX ounces per square under the pressure of the air entering from the wind boxes. This will result in a complete combustion of the coal. The air is also delivered to the hopper casing, and, therefore, into the top of the fuel chamber. This will cause an air seal to be formed between the hopper and the fuel chamber, so as to prevent the escape of gases through the hopper. This is necessary in a furnace construction of this type, since the gases are not drawn from the fuel chamber as in a gas producer, but the gases are delivered under pressure to the heating chamber of the reverberatory furnace. This air also has the functions of keeping the hopper and the lining cool, providing means for betten completing the combustion of the heating gases, and for regulating the temperature thereof.

In the operation of the furnace, a bed of coal is formed of such a thickness, and the furnace is so controlled, as to cause the gases to be discharged at the required temperature, of the required composition, and in the required quantity. These factors may be controlled by varying the feed of the coal, by varying the stoking and purging operations, and by varying the normal quantity of air as delivered by the twyers and by the ash pit. The feedlng means, and ram operating mechanisms are, therefore, so adjusted, and the valves 78 and 39 are so set, that a gas of the desired quantity and composition, and at the required temperature, is delivered. If the quantity of heating gas to be-delivered 1s thereafter to be varied, it is only necessary to vary the feeding, stoking and purging operating means, and regulate the pressure and quantity of air delivered to the furnace chamber. This adjustment of the feeding, stoking and purging means canbe simultaneously accomplished by varying the throw of the rock shaft 44 by adjusting the rod with respect to the arm 64, and the air can be controlled by adjusting the valves 78. The air connections need not ordinarily be varied, except when the feeding, stoking and purging means are varied, as the quantity and pressure of the air will adjust itself automatically to the varying conditions in the furnace. It will, therefore, be seen that the quantity of heating gas delivered can be varied, while its quality and temperature will remain practically the same.

The long pipes 75, which are of such area and capacity as to be considerably less than the combined areas or capacities of the twyers and the ash pit openinginto the furnace, causes the air to be delivered by the twyers and through the ash pit at a normal pressure considerably less than the pressure in the ipe 76, as pointed out above, and this norma pressure will be maintained as long as the resistance of the fuel bed to the air passing therethrough remains normal. If now the fuel bed should become clogged by soft spots forming in the coal bed causing clinkers, then,since the effective area of the passages through the fuel will be decreased, the amount of air discharged therethrough at normal pressure will be decreased. This will cause an accumulation of the pressure in the wind boxes and ash pit, which accumulation will increase directly as the resistance in the fuel bed increases, and can reach the full value of the comparatively high pressure in the pipe 76. This increasing pressure will cause the air to force through the fuel bed so as to blow holes therein and cause a hot fire to stopv and prevent clogging of the fuel bed. As soon as the clogging is stopped and the resistance of the fuel bed goes back to normal, the pressure goes back to normal. It will thus be seen that, under normal conditions, the air will be maintained at normal pressure, but that, as the conditions become abnormal, the pressure will rise so as to reestablish normal conditions. The normal pressure is maintained by making the pipe 75 of small diameter and capacity, as compared to the capacity of the pipe 76, and the capacity of the twyers and ash pit, and the capac ity of the pipes 75 can be varied, within small limits, by the valves 78. These valves 78 are, however, only intended to vary the pressure within small limits, to adjust for varying quantities of gas required, and for varying conditions and properties of the fuel used, as the pipes 75 themselves are depended upon to control the normal pressure. By making these pipes comparatively long they will have a dampening effect on sudden changes in the pressure of the air as delivered by the twyers and ash pit, so as to prevent fluctuations in operation, and maintain the operation uniform and constant. By connecting both the blast pipes 75 and the pipe 38 with the main supply pipe 76, fluctuation in the pressure of the air in the main supply pipe will cause like fluctuation in pipes 78 and 35, so that no irregular operation will result.

It is obvious that various changes may be made inthe details of construction, within the scope of the claims, without departing from the spirit of this invention, and it is, therefore, to be understood that this invention is not to be limited to the specific construction shown and described.

Having thus described the invention, what is claimed is:

1. In a coal burning metallurgical heating furnace, adapted to deliver dry heating gases under pressure to form a dry reducing atmosphere, a fuel chamber adapted to receive a bed of fuel from which the dry gases are generated, an ash pit at the bottom of said chamber, means for maintaining air under pressure in said ash pit, a hopper casing at the upper end of said chamber to disand to said hopper casing adapted to control the characteristics of mosphere.

2. In a coal burning metallurgical heating furnace adapted to deliver dry heating gases under pressure to form a dry reducing atmosphere, a fuel chamber comprising a vertical shaft adapted to receive a bed of fuel from Which the dry gases are generated, means for admitting the fuel from the top of said shaft, means for admitting air under pressure to the bottom of said shaft onto the fuel bed adapted tocontrol the characterthe dry reducing at istics of the dry reducing atmosphere, and" means for admitting the air under pressure to the top of said shaft in a manner and in sufiicient volume to form an air seal.

3. In a coal burning metallurgical heating furnace adapted to deliver dry heating gases under pressure to form a dry reducing atmosphere, a fuel chamber comprising a vertical shaft adapted to receive a bed of fuel from Which the dry gases are generated, means for admitting the fuel from the top of said shaft, means for admitting air under pressure to the bottom of said shaft onto the fuel bed, means for admitting air under pressure to the top of said shaft in a manner and in sufficient volume to form an air seal, and means for controlling the supply of air adapted to control the characteristics of the dry reducing atmosphere.

4. In a coal burning metallurgical heating furnace adapted to deliver dryheating gases under pressure to form a dry reducing atmosphere, a fuel chamber adapted to receive a bed of fuel from Which the dry gases are generated, means for supplying air to the bottom of said chamber adapted to control the characteristics of the dry reducing atmosphere, and means constructed to automatically increase the pressure of the air supplied when the fuel bed resistance to the air is increased.

5. In a coal burning metallurgical heating furnace adapted to deliver dry heating gases under pressure to form a dry reducing atmosphere, a fuel chamber adapted to receive a bed of'fuel from Which the dry gases are generated, means for supplying air to the bottom of said chamber adapted to control the characteristics of the dry reducing atmosphere, and regulating means adapted to maintain the air pressure normal With normal resistance of the air through the fuel and automatically increase the air pressure When the resistance increases.

' 6. In a coal burning metallurgical heating to control the characteristics of the dry reducin atmosphere.

7. 1% a coal burning metallurgical heating furnace adapted to deliver dry heating gases under pressure to form a dry reducing atmosphere, a fuel chamber adapted to receive a bed of fuel from which the dry gases are generated, means for supplying air to the bottom of said chamber adapted to control the characteristics of the dry reducing atmosphere, and regulating means adapted to automatically increase and decrease the air pressure as the resistance offered by the fuel bed increases or decreases.

8. In a coal burning metallurgical heating furnace adapted to deliver dry heating gases under pressure to form a dry reducing atmosphere, a furnace chamber adapted to receive a bed of fuel from which the dry gases are generated, means for feeding, stoking and purging the fuel, means for supplying air to the furnace chamber, and means for varying the operation ofsaid feeding, stoking, purging and air supplying means adapted to control the characteristics of the dry reducing atmosphere.

9. In a coal burning metallurgical heating furnace adapted to deliver dry heating gases under pressure to form a dry reducing atmosphere, a fuel chamber adapted to receive a bed of fuel, means for delivering air under pressure beneath the bed of fuel, and means for controlling the air pressure comprising a main air supply and reducing connections between the same and the delivery to the fuel bed.

10. In a coal burning metallurgical heating furnace adapted to deliver dry heating gases under pressure to form a dry reducing atmosphere, a fuel chamber adapted to receive a bedeof fuel, means for delivering air under pressure beneath the bed of fuel, and means for increasing the air pressure at the point of delivery to the fuel bed as the resistance ofiered by the latter increases.

11. In a coal burning metallurgical heating furnace adapted to deliver drv heating gases under pressure to form a dry reducing atmosphere, a fuel chamber adapted to receive a bed of fuel, means for supplying air under pressure beneath the bed of fuel adapted to control the characteristics of the reducing atmosphere, and means for varying the quantity Without varying the quality and temperature of phere.

the reducing atmostrol the characteristics of the reducingatmosphere,

said air supplying means being adapted to deliver the air to the fuel at a 10 normal pressure below the main air supply pressure and to vary this delivery pressure in accord with the resistance offered by the fuel bed to the passage of air therethrough.

In testimony whereof we afiix our signatures, said EDWARD C. 'ALKER this 20th day 15 November, 1915, and said Asrrunnmn S. Moses thls 3rd day of November, 1915.

EDWARD C. WALKER.- ASIlELEIGI-l S. MOSES. 

